This invention relates generally to rubber compositions, and more particularly, to an isoprene rubber belt material for flexible paper feed belts in sheet feeders, transporters or separators in xerographic machines.
The development of high speed xerographic machines has brought about the need for reliable systems which are capable of feeding, transporting, separating and sorting paper and other materials in and through such machines at high speeds. One of the most reliable modes of feeding, transporting, separating and sorting paper and other materials throughout such machines is by means of flexible, endless belts. Examples of such belt means are found in U.S. Pat. No. 3,468,834 issued to Stange et al where a flexible separator feed belt formed from a material having a high coefficient of friction is connected between a separator drive pulley and a separator idler pulley. Sheet feeder belts which include endless loops of elastic material supported for movement about pulleys are also described by Stange in U.S. Pat. 3,768,803.
Prior to the introduction of high speed systems, standard rubber belts were sufficient for the manufacture of paper feed belts, paper transporting belts, paper separating belts and paper sorting belts where stress upon such belts was minimal, and there was little or no mechanical or physical degradation due to dynamic stress upon the rubber. Thus, belts for such systems could be manufactured from conventional rubbers, such as, natural rubber, neoprene rubber, polyacrylonitrile, butadiene/styrene rubbers and even stock isoprene rubber. However, when such conventional rubbers are used in the manufacture of flexible belts for use in high speed systems, mechanical degradation of the rubber occurs from the mechanical stress due to high speeds, and the useful life of such belts is shortened considerably requiring early replacement and loss of use of the system while the belt is being replaced. Furthermore, belts manufactured from conventional rubbers or elastomers are also characterized by reversion due to overcure and are easily degraded by oxidation at elevated operating temperatures.